Mold for casting stereotype printing plates



Dec. 1-5, 1936. w, F, HQCK 2,064,117

MOLD FOR CASTING STEREOTYPE PRINTING PLATES Original Filed June 2, 19522 Sheets-Sheet 1 INVENTOR.

Dec. 15, 1936. w. F. HUCK I 2,064,117

' MOLD FOR CASTING STEREOTYPE PRINTING PLATES Original Filed June 2,1932 2 Sheets-Sheet2 IN V EN TOR.

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Patented Dec. 15, 1936 UNITED STATES.

MOLD FOR CASTINGv STEREOTYPE PRINTING PLATES William F. Huck,RichmondHill, N. Y., assignor,

by mesne assignments,

toR. Hoe & 00., Inc.,

New York, N. Y., acorporation of New York Original application June 2,1932, Serial No. 614,910. Divided and this application April 13, 1934,Serial No. 720,351

8 Claims.

The present invention, which is a division of copending application No.614,910, filed June 2, 1932, for Molds for casting stereotype printingplates, relates to improvements in molds for casting stereotype printingplates, and has for its object the provision of certain means that willobviate the tendency of stereotype plates that are cast in molds ofconventional type to become deformed when removed from the mold.

Another object is to provide a novel method and means for equalizing theabsorption of heat from stereotype plates during the casting operati'on;

Another object is to provide a stereotype plate casting moldof a designand construction particularly adapted to produce printing platescomparatively free from internal stresses resulting in deformation and atendency of the finished plate to become warped and develop cracks afterremoval from the machine.

A further object is the provision of animproved casting box or chamberfor a stereotype plate casting machine that will insure the productionorcasting of printing plates of uniform characteristics and homogeneousstructure.

A still further object is to provide means for delaying the cooling ofselected areas of. a stereotype'plate during the casting operation inorder to assure the production of printing plates free from defects instructure or configuration.

Other objects and advantages will. be found in the details hereinafterset forth.

As is wellknown to those skilled in the printing art,. one of: thechiefdifiiculties encountered in the castingv of printing plates hasbeen the marked tendency towards deformation. of. a certain percentage.-of printing, plates whenv taken from the casting chamber or box. This isdue to theuneven solidification of the molten stereotype metal in themold whereby internal stresses and strains are developed in the printingplate arising from the unequal cooling of the opposite sides of: thesaid plate or the unequal absorption oi. heat fromthe printing; platewhile still in the mold, by the opposite sides of the casting chamber.

The. matrix which lines one side of the casting chamber during thecasting process, is of a composition having poor heat conductingproperties, consequently the molten metal engaged against said. matrixwill cool more slowly than the molten metal that is in contact with theopposite and. bare wall of the, casting chamber, where it cools rapidly.The difference in cooling produces or sets up stresses in the exteriorof the plate, which will in many cases cause the said plate when takenfrom the casting chamber to warp or to develop fissures and cracks, andin curved plates there is also a tendency for the curved edges. tostraighten. The: matrix side; of 1 the. plate by the cooling processabove indicated is subjected. to tensional stresses, which is opposed bycompressional stresses in the opposite side of the plate. Upon removalof the curved plate from the mold, these force couples will cause it: tocave-in along its straight edge and open-up in its curvature. In:particular, the edges or. margins ofv stereotype. plates have beenfound: to cool more rapidly than the body portion resulting in. atendency to deformation in the finished plate which in the case of acurved? plate frequently" produces a saddle formation and opening up ofsame.

In accordance with' the present invention, and as forming an importantfeature thereof, a stereotype plate casting device is provided having anovel mold: or. casting chamber particularly adapted toprevent:unequalscooling of the oppositesides; of, a: printingwplate.

The: invention will be best understood when taken: in connection withthe accompanying drawingsin which:

Figure l is a side elevational view, partly in section, of a stereotypeplate casting machine-embodying the invention;

Figure 21 is a front elevational view' as seen in the direction ofthe-arrow 2 of Figure 1;

Figure 3 is an enlarged vertical sectional view of a portion of themechanism shown in Figure 1, with parts broken away;

Figure 4 is a transverse sectional viewtaken onv line 4'-4 of Figure 3,looking in the directionof the arrows;

Figure 5is a view of the core member as viewed in, the direction of thearrow 5 of Figure 3;

Figure. 6; is a: longitudinal sectional view taken on line 6-6 of Figure5, looking in the direction of the: arrows; and I Figure 7 is atransverse sectional view taken on line 1-1 of Figure 5, looking in thedirection of the arrows.

where it is operative portion ll of the casting mold may be manipu-.

lated or moved by the handles 3, and since the trunnions l2, l3 andtracks |6, I! are arranged and located to support the'said body portionll of the mold in balanced condition at all angles or positions, it willbe understood that same may be handled with comparative ease and withoutundue strain or effect on the part of the operator. The cooling of thecore member ID is pro-: vided by a water jacket or chamber I 9 which mayhave a valve controlled inlet pipe 20 and an outlet pipe 20'.

In accordance with the present invention and for the purpose ofpreventing too rapid a cooling of the edges or margins of a stereotypeplate, the member ID is formed or provided with a recess or pocket 2| inwhich heat insulating material 22 is secured. In addition to theinsulating material 22, a sheet or web of insulation 23 that may bepaper or other suitable material for the purpose of preventing too rapida cooling of one side or face of the body portion of the stereotypeplate, may be secured to or wound on spindles or bars 24, 25 havingsquared upper ends 24', 25, the said spindles being rotatably secured tothe frame or support of the core member ID and mounted in sockets as at26 fastened thereto. Suitable means for locking the spindles 24, 25 tohold the sheet material 23 securely in the casting chamber are provided,which may be pawl-engaged gears 21, 28 on the respective spindles 24,25. a

When the rods on which the paper insulation is engaged or wound, isturned, the said paper insulation, which is preferably of heavy stock,will be drawn tightly against the core wall formed by the fixed memberIII, the coacting opposite or matrix wall being formed by the movable orswingable mold member H, which is lined by the matrix C. In order toclamp the sheet of paper 23 the use of which latter is optional, a pairof clamping members are employed, each consisting of a band or strap 29,the ends 3|, 32 of which are secured by screws 33 to bars or shafts 34,in which adjusting screws 35, 36 are mounted.

Each of the adjusting screws 35, 36 has one end engaged in a pocket orrecess formed in the fixed mold member. As the screws 35, 36 are turned,the adjacent bar 34 will be moved towards or from the fixed member IDand the strap 29 engaged against the sheet of paper 23, or releasedtherefrom. The sheet of paper augments the action of the insertedsection of insulation in preventing a too rapid absorption of heat fromthe cooling plate by the wall of the core ID of the casting box oppositethe wall against which the matrix C is pressed.

The casting chamber or box formed by the coaction of the fixed andmovablemembers I and I is closed at the bottom by the usual head gauge38 and at the sides by hinged side bars designated generally at 39. 1

In order to lock the body portion or movable mold member II to the coremember l0 preparatory to casting a printing plate 40, an operating lever4| is provided. The lever 4| is fastened to a shaft 42 having securedthereto a crank arm 43 hinged to one end of a link 44 the other end ofwhich is similarly connected to a second crank arm 45 which is securedto a shaft 46. The shaft 42 has a pair of locking members 41, 48 securedthereon, each of said locking membe'rs'being provided with a slot 49which is adapted to receive a pin (not shown) fastened in the movableportion of the machine. The shaft 46 is also provided with similarlyformed locking members 52 which coact with pins or members (not shown)in the movable mold member When the handle 4| is manipulated the lockingmembers 41, 48, 5|, and 52 will be simultaneously moved to lock the bodyportion or movable mold member H to the core member l0 or to releasesame when desired in accordance with well known practice. A head gauge38 is provided which may have operating handles 53. For the purpose ofretaining the movable mold member in the horizontal position shown indotted lines in Figure 1, a suitable retaining device, hinged to theframe 9 and indicated generally at 54, is also provided.

In operation and in accordance with the invention as described above,the casting chamber is prepared by securing a matrix C to the bodyportion or movable mold member and then optionally confining a sheet ofinsulating material, preferably paper, to the inner wall of the coremember ID by the clamping member or band 29 which is adjusted to clampthe paper or web 23 with the desired pressure by turning the spindles24, thereby securing or adjusting the said paper 23 over the inner wallor surface of the core member ll] of the casting box. Molten metal maynow be poured into the open top of the mold to form a stereotype plate40. The paper 23 will tendto preventatoo rapid chilling of the bodyportion of the printing plate,-while the insulating material 22 securedin the recess 2| will act in a manner to prevent too rapid a cooling ofthe edges of the cast printing plate, where the major portions of thestresses due to uneven cooling are apt to take place while it is stillin the casting box, for reasons pointed out above. The cooling of theplate at the edges and on both sides of the body portion will now beapproximately equal and as a consequence the said plate will have ahomogeneous molecular structure so far as internal and marginal stressesand strains are concerned. The insulating material 22 it is to beunderstood plays the major part in preventing deformation of thestereotype plate due to the rapid cooling of the edges or margins of thestereotype plate as compared to the body portion.

If desired, the movable mold member also may be recessed in the mannerillustrated with regard to the fixed or core member in order toaccommodate insulating material. As the distortion due to the unequalcooling occurs mostly at the edges of the plate, it will be understoodthat heat insulating material on the margins of either or both of themovable and fixed mold members will retard the cooling of a plate duringthe process of formation after the molten metal has been poured in themold. In Figures 6 and 7, and from one side of Figure 4, the insulatingmaterial 22 has been omitted from the said recess 2| for the purpose ofclearer illustration.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or essential attributesthereof, and it istherefore desired the present embodiment be consideredin all respects as illustrative and not restrictive, reference being hadto the claims rather than to the foregoing description to indicate thescope of the invention.

What I claim is:

1. In a mold for casting curved stereotype printing plates, a concavemold member and a coacting convex mold member, means for securing amatrix to the concave mold member, shallow recesses extending along theedges of said convex mold member, and heat insulating material in therecesses.

2. In a mold for casting curved stereotype printing plates, a concavemold member and a coacting convex mold member, means for securing amatrix to the concave mold member, a recess in the convex memberextending along its side edges and along its bottom edge only, and heatinsulating material in the recess.

3. In a mold for casting curved stereotype printing plates, a concavemold member and a coacting convex mold member, means for securing amatrix to the concave mold member, recesses along the side edges andalong the bottom edge only of the convex mold member, heat insulatingmaterial in the recesses, and means for securing a sheet of paper overthe casting surface of the convex mold member.

4. In a mold for casting stereotype printing plates, a first mold memberand a second mold member which coact to form a casting chamber, meansfor securing a matrix to the first mold member, recesses in the secondmold member along three of its edges, and heat insulating material inthe recesses.

5. In a mold for casting stereotype printing plates, a first mold memberand a second mold member which coact to form a casting chamber, meansfor securing a matrix to the first mold member, a recess in the secondmold member along its side and bottom edges only, and heat insulatingmaterial in the recess.

6. In a device of the kind described for casting stereotype printingplates, a movable member having a wall provided with means on an innersurface thereof for securing a matrix thereto, a fixed member having awall provided with marginally positioned means for securing heatinsulating material thereto, and screw threaded means connected to thefixed member for adjustably clamping sheet insulating material to thewall of the fixed member, whereby molten metal poured into a chamberenclosed by the said walls of the fixed and movable members will form aprinting plate free from deformation and stresses generally due tounequal absorption of heat while cooling.

'7. In a device for casting printing plates, a movable member having amatrix receiving inner wall, a fixed member having a wall provided withrecesses arranged along said wall at the margins alone thereof foraccommodating insulating material, and means including a band fastenedto a member secured and adjustable relatively to the fixed member forpositioning sheetinsulating sheet material against the last mentionedwall.

8. In a stereotype plate casting mold, a first mold member and a secondmold member each having a wall and arranged to cooperatively form acasting chamber closed at the bottom and sides and open at the top, thefirst mold member having a relatively wide and shallow recess formed inits wall and arranged adjacent the bottom and side edges alone of thecasting chamber, and heat insulating material in the recess; whereby thecooling of the side and bottom edges of a plate cast in said mold willbe retarded.

WILLIAM F. HUCK.

